This invention relates to surgical scissors, and more particularly to scissors of slender design and flexible structure for endoscopic surgery with convenient manual actuation.
Endoscopic surgery commonly requires manual manipulation of surgical instruments that are introduced into a surgical site within a patient through elongated cannulas containing one or more interior lumens of slender cross section. Endoscopic surgery to harvest a saphenous vein usually involves an elongated cannula that is advanced along the course of the vein from an initial incision to form an anatomical space about the vein as connective tissue is dissected away from the vein.
Lateral branch vessels of the saphenous vein can be conveniently isolated and ligated within the anatomical space under endoscopic visualization using surgical scissors that can be positioned and manipulated through the elongated cannula. Such surgical procedures are commonly employed in the preparation of the saphenous vein for removal from within the anatomical space for use, for example, as a shunting or graft vessel in coronary bypass surgery.
One difficulty commonly encountered using surgical scissors to ligate vessels within the confines of limited anatomical space formed along the course of the saphenous vein is that the slender configuration of surgical scissors suitable for introduction into a remote surgical site through a lumen of an elongated catheter precludes attaining much mechanical leverage for opening and closing a pair of mating scissor blades about a pivot axis. Surgical scissors for use in endoscopic surgical procedures commonly include a pair of conventional scissor grips having thumb and finger holes on one or more levers, or include a grip lever mounted at a proximal end of a slender body that is disposed to extend through a lumen between proximal and distal ends of a cannula. Scissor blades pivotally mounted at the distal end of the slender body undergo relative shearing movements in response to sliding movement of a rod or wire within the slender body under control of the manually-manipulated scissor grips at the proximal end. However, such scissor grips are commonly shaped to fit right hand thumb and forefinger for movement in a substantially vertical plane and are not readily conducive to convenient manual manipulation in other orientations that may be required in order to align the scissor blades at the distal end of the slender body for a particular surgical procedure. In addition, the scissor grips include substantial bulk in order to fit an average span of thumb and forefinger of a surgeon, which bulk becomes objectionable during surgical procedures performed in confined quarters and commonly interferes with other instruments and attachments that also emanate from the proximal end of a cannula that is configured for such surgical procedures.
In accordance with the illustrated embodiment of the present invention, surgical scissors include scissor blades mounted at the distal end of a slender, flexible body for manipulation under control of a single lever mounted at the proximal end of the slender body. The lever is supported in a slender housing of low profile that is attached to the elongated body of the surgical scissors. The lever provides substantial mechanical advantage and need only be actuated fore and aft in substantially normal alignment with the elongated body, using thumb or fingers of either hand while the housing is disposed in any convenient orientation, thereby greatly enhancing the versatility of the scissors as a surgical instrument. In addition, the scissor blades may also contain electrodes or heater elements for supplying energy from external sources to cauterize as well as shear tissue at a remote surgical site in a patient. In one embodiment, the housing and components of the surgical scissors are fabricated to facilitate rapid assembly and ergonomic considerations. Half-shell segments of the housing are disposed to receive sub assemblies that comprise the surgical scissors, and are assembled in mating configurations to constrain the components and complete the surgical scissors.